1 Introduction

Calorimetry and thermal methods have been practised in the Pharmaceutical Industry for some time. ^{[1] , [2]} This chapter is, however, only concerned with applications of isothermal heat conduction microcalorimetry in the Pharmaceutical Industry (Chapter 10 describes Industrial Applications of Flow microcalorimetry, a topic not covered here). A feature observed in recent years is the growth (albeit small) in the number of Companies that offer broadly equivalent-in-performance microcalorimeters that operate over a range of modes ( e.g., Thermometric AB, J rfalla, Sweden; Setaram, Caluire, France; Calorimetry Sciences Corporation, American Fork, UT, USA). Thus, these manufacturers all supply instruments with nanowatt detection limits complete with a range of specialised options for titration, humidity control, perfusion, etc. (for a general review of sensitivities of different instruments, see ^[3]). In addition, all supply solution calorimeters, high sensitivity scanning calorimeters and, more recently, multi-channel instruments ( e.g., Thermometric offers a 48-channel instrument). These multi-channel calorimeters generally sacrifice some of their sensitivity and detection limit capacity in the pursuit of higher throughput rates. This chapter will not describe in any detail the operation, design and techniques of microcalorimetric experiments; it will, however, concentrate on the applications to which microcalorimetry has been put. Calorimetry has several advantages that are of significance to pharmaceuticals. It is non-invasive, non-destructive and capable of dealing with all phases and with mixed phases. Thus, it can accommodate solids, liquids, gases (and their combinations), suspensions, emulsions, creams, ointments, etc.

However it is essential,...